Explosive actuated pin driver



`10.1.22,1963 ApwoLF 3,074,070

'ExPLosIvE ACTUATED PIN DRIVER original `Fi1ed Aug. 21. 1957 /n ven for:

United States Patent O Claims priority, application Switzerland Aug. 25, 1956 2 Claims. (Cl. 1--44.5)

This application is a divisional Vapplication of applicavtion Serial No. 679,450 led August 2l, 1957.

VIt is well known practice to use a pin designed to be driven, under the action of a gas-pressure, into hard material (such as wood, cement, concrete, etc), anda liringapparatus to do so, the barrel of which, at the rear end of the bore, is joined, through a shoulder, .to a loading chamber which is, on the rear, obturated by a cap which comprises a guide for the `tiring pin ofthe propulsive charge which is to re the pin.

`In known devices of this type, there is, in the loading chamber, a cylindrically shapedcartridge holder, in the axial hole of which'the cartridge is engaged. After each liring, the cap is removed and the cartridge holder is taken out of the loading chamber, and thecartridge case is ejected out of the holder, by means of a rod acting from the front.

However, such ejection of the cartridge clases often results in difficulties, because, if the cartridge holder is not perfectly clean, the case jams, due to the action of the explosion pressure.

Even when the cartridge'holder ismade of appropriate steel, diiiculties appear after a rather short use, and lead to trouble in service. On the other hand, ,whenthe pin is fired, a part of the exploding gases escape through lthe space between the cartridge holder and the loadingy chamber, and reach the spacesituated behind the cap of the `tiring device. Aside from the dirtying of parts which thus occurs, and which leads to trouble in use, the resulting loss of pressure in 'the barrel lowers the power of ejection ofthe pin from the barrel. Similar insu'iciencies result from the loss of gases which, in known devices, occurs as a part of the gasesrpasses between the wall of the bore and the pin. The total lossof gases, at rear andfront, is such thatthe pin is driven into the material (which it has to penetrate) with a power considerably and undeterminably lower than its pre-determined value. The object of the present invention is to obviate to the above drawbacks. It covers,on,the one hand, a pinammuntion unit, in which the pin is designed to be driven, under gas pressure, into hard materials,` and, on the other hand, Aa device ofi theabovementioned type, forfiring such pins, said unit being characterized by the fact that it comprises a block made of distortable material, having, on the one hand, a rear part shaped to correspond to the shape of the loading chamber, an annular shoulder designed to come into contact with the shoulder of the rear end of the barrel, and an axial cavity designed to receive the propulsive charge, which is closed at the rear by the holder of the primer, and on the other hand, a front part forming a wad, comprising a guiding surface which corresponds to the bore of the barrel and presents, towards the front, a lodging into which is forced the rear end of the pin, to which the said front part serves as centering means, the bottom of the axial cavity being level with the shoulder, in such a way that the pressure of the gases produced by ignition of the charge, entails, on the one hand, under the action of expansion, a gas-tight closing of the rear part of block against the wall of the loading chamber and, on the other hand, the shearing, driving back, and expulsion of the front part of the block by -means of whichl the firing `-the shot-is tired.

3,074,070 Patented Jan. 2 2,

vwhich serves as guide to the pin, as well as lgas-proof tightening of this part of the block against the wall 0f the bore.

`It vis not absolutely vnecessary that the charge should be contained in a cartridge, and therefore that the block should act only as Va ,cartridge holder, since there is no reason why the charge could not be directly Alodged vin axial cavity of the rear part ofthe block, this vcavity being obturated by the part supporting .the primer. However, even if a cartridge iS used, n0 trouble can occur when the case of the Vcartridge is ejected, since the cartridge holding block is used only once, and the fresh annnunition which replaces it is in the form ofanother cartridge ready for use and lodgedin such a-bloek.

The said block maybe made of any distortable ,material answering to requirements, preferably, of course, some cheap ,andeasily workable material; lfhe'power of explosion to which the'block is submitted 'being rather high, there is no need of imposing high distortabilitycharacteristics, so Jthat ,the block may be made of material neither particularly elastic nor adhesive, s uh as ar e, for instance, the known polyamides.` jFor example, l hard rubber may be used, or various synthetic products, particularly synthetic resins (cellulose acetate).

lOn-the annexed drawing, vsome examples of embodiment Vof the invention aredisclosed,

lFIGnl is a section view ofone embodiment, theparts being ready'for tiring.

FIG. -2 is a-view similar t o various parts after tiring.

FIGS. 3 and I4 are similar views showing two dilerent embodiments of themammunitivon holdingvblock.' l

In FIG; l, the -`firing device comprises a b arrel 1, the Vrearend of which has a cylindrical widening 2, behind which is situated the cylindrical-loading chamber 3. The `latter is providedyin apart of the-body 4 of -the ring device, this part having, atpits rear end, a threadupn which is screwed an obturating cap Sprovided with corresponding threads. This part has an 'axialfhole in which the rst one, disclosing the 4is guidedtheliring pin 6. rI'he rear vend of the liiringpin 6 protrudes-frorn the obturating capS, andris subjected to the action of a known device; herein not represented, pin is driven forwar d when In the .ring position disclosed `in FIG. "1, thepin-H, of l:1t-conventional type, isin axial positionfinthe rear part bore and serving as lcentering, means. -Therear part 11,-1

of the` block is ,shaped to correspond .to -thecontour .of the loading chamber 3. Therefore, it has, in impart adjacent to the front part 9, an annular surface in close contact with the shoulder 12 through which the barrel is joining, towards the rear end of the bore 8, with the cylindrical wall of the chamber 3. In the rear part 11 is, moreover, provided a central cylindrical cavity 13, which opens to the rear. In this cavity, which is substantially level with the shoulder 12, is lodged a cartridge 14 which contains the charge of powder dosed in a convenient way, the bottom of the cartridge 14 containing the primer, being placed in the cavity and obturating it towards the rear.

The barrel 1 is mounted in such a way that, after removal of the cap 5, it can be axially slided through the chamber 3, driving positively the block, while it cannot 'slide towards the front, this being prevented by shoulder 15 of the body 4, the front face ofthe widening 2 bearing against said shoulder 15.

The front part 9 of the block B is designed to constitute an axial projection of the rear part 11, this projection having a cylindrical recess 16, open towards the front, in which is engaged the rear end of the pin 7, which is threaded. Said recess may be provided with a thread corresponding to that of the pin, so that the pin maybe screwed onto it and unscrewed. However, practically, it is sufficient to give to this recess 16 the shape of a cylindrical hole, or of a slightly truncated cone, in which the rear yend of the pin may be engaged. Further, of course, the rear end of the pin may be embedded in part 9.

When the shot is tired, by driving forward the tiring pin 6, the pressure produced in the cartridge 14, which propagates in the cavity 13, and which is rather high, results, as shown in FIG. 2, in a barrel shape swelling of the wall 17 of the cartridge and of the rear part 11 of the block B, until close contact is obtained with the wall of the chamber 3, this contact being close enough to be gas-tight. Moreover, the gas pressure produces a sudden separation of the front part..9 from the rear part 11 of the block, in the point of the lesser resistance, as it is indicated by the breaking surface 1-8 shown in FIG. 2. This is accompanied by the expulsion of the front part 9 which guides the pin. Said front part 9, expands, due to the inertia, until it is gas-tightly pressed against the wall of the bore -8, forming thus a wad. The cavity 19 which receives the gases produced by the explosion, behind the front part'y 9 of the block B, is thus hermetically obturated, towards the front as well as towards the rear, so that, without any loss of pressure, the whole volume of gas produced by explosion can act upon the pin and drive it with a well determined force out of the barrel.

The recoil produced by the expulsion of the pin 7 with the front part 9 of block B is transmitted to the tiring device, being however, distributed, for the main part, directly over the body 4, with a frictionally adhering action, dueto the tightness hereinabove mentioned, of the rear part 11 of the block B against the wall of the chamber 3, and for the remainder, over the obturating cap 5. Thus, there is practically no transmission of the recoil to the threaded link between the cap and the body 4, which is a particularly desirable feature.

After completion of the tiring, the cap 5 is unscrewed from the threaded body 4. The barrel 1 is then taken out, by sliding it rearwards in the body 4, thus pushing out of the loading chamber 3 the rear part 11 of the block situated in said loading chamber.

'It is to be noted that the bottom of the cavity 13 of the block B is slightly on the downstream side with respect to the shoulder 12. This particularity is very important, because when the block B is put in place in the ring device, it presents the lower resistance section at the level of the shoulder 12, in such a way that when the shot is tired, there will remain practically nothing of the front part 9 of the block B within the barrel.

This feature facilitates the ejection of the rear part 11 55 of this block,

After the barrel has been pushed forward, a new pin with a loaded block has been pushed in the loading chamber, and the cap 5 has been screwed on, the device is ready for another shot.

The embodiment of the block shown in FIG. 3 differs from that shown in FIG. l only by the fact that the charge of powder 2% is directly in the cavity of the rear part 11 of the bloc-k B, and that this cavity is closed by a disc 21 provided with the primer, the edge 22 of this disc being lforced into an annular groove provided close t-o the edge of the cavity, in the Wall of the latter. The disc 21 has, consequently, the same function as the bottom of the cartridge, in the embodiment shown in FIG. 1, which bottom, in as much as itacts as support for the primer, obturates the rear part of the cavity.

The embodiment of the block shown in FIG. 4 differs from that of FIG. 1 only bythe fact that the rear part 11a of the block Ba has the shape of a truncated cone 23, the narrow part of which is directed towards the front. In this case, the wall of the loading chamber provided in the body 4, must have a corresponding truncated cone shape. This truncated cone presents, however, at the point where it is joined with the front part 9, also an annular surface 24, which, when the device is loaded, comes into contact with the shoulder through which the barrel, at the rear end of the bore, is joined with the loading chamber. This shoulder is, then, because of its conical shape, smaller than the shoulder 12 of the embodiment shown in FIG. 1.

What I claim is:

1. In a ring device for driving pins into hard material under gas pressure comprising a body provided with a bore, said body being provided at the rear end with a cavity coaxial with said bore, said bore opening into said cavity, a rear obturating member detachably securable in the outer end of said cavity, said cavity being of larger diameter than said bore to define a shoulder therewith at their junction, said cavity providing a chamber to receive an ammunition unit carrying the pin, a barrel positioned in said bore for sliding movement relative to said body, said barrel having a rear enlarged portion adapted to move in said cavity, said por-tion having a shoulder adapted to abut said -irst shoulder, said barrel, when actuated rearwardly following detachment of the obturating member, providing ejection of the spent ammunition unit from the cavity.

2. A tiring device as claimed in claim 1, wherein the barrel has a front part which protrudes from said body, so that said barrel may be driven by its front part into said body for ejecting, by its rear part, said spent ammunition out of the cavity.

References Cited in the tile of this patent FOREIGN PATENTS 

1. IN A FIRING DEVICE FOR DRIVING PINS INTO HARD MATERIAL UNDER GAS PRESSURE COMPRISING A BODY PROVIDED WITH A BORE, SAID BODY BEING PROVIDED AT THE REAR END WITH A CAVITY COAXIAL WITH SAID BORE, SAID BORE OPENING INTO SAID CAVITY, A REAR OBTURATING MEMBER DETACHABLY SECURABLE IN THE OUTER END OF SAID CAVITY, SAID CAVITY BEING OF LARGER DIAMETER THAN SAID BORE TO DEFINE A SHOULDER THEREWITH AT THEIR JUNCTION, SAID CAVITY PROVIDING A CHAMBER TO RECEIVE AN AMMUNITION UNIT CARRYING THE PIN, A BARREL POSITIONED 